In many engines with fuel injection systems, it is desirable to supply liquid fuel to the fuel injector or injectors from a fuel pump that continuously delivers a flow rate of liquid fuel sufficient to supply the maximum fuel demand of the engine. Therefore, under engine operating conditions, wherein the engine has a lesser fuel demand, there is an excess of fuel being supplied from the fuel pump. This is especially true when the engine is idling and has an extremely low fuel demand.
In such systems, a bypass regulator is utilized to provide a bypass fuel flow path downstream of the fuel pump through which excess fuel delivered from the fuel pump is returned to the fuel tank. The fuel pressure regulator may be located within the fuel tank immediately downstream of the fuel pump to bypass excess fuel delivered from the fuel pump directly into the fuel tank. In some applications, the fuel pressure regulator may be located downstream of an engine fuel rail or injectors to bypass excess fuel to the fuel tank through a fuel return line. In this way, the pump can be continuously operated to maintain a high rate of fuel output so as to be able to accommodate a rapidly increasing demand for fuel by the engine.